Qt5DesignerConfig.cmake gone from Qt 5.6 on Windows?

So I wanted to compile VTK 6.3 on Windows 10 with Qt 5.6 and got a message saying Qt5DesignerConfig.cmake is not found. And indeed it seems to be missing from Qt 5.6 on Windows. It is present in Qt 5.6 on Mac and in Qt 5.4 on Windows. There are only a Qt5Designer.dll and a Qt5DesignerComponents.dll in the C:\Qt\Qt5.6.0\Tools\QtCreator\bin folder.

Does anyone know if this is intentional, and if so, which settings should be used to get around the problem?

CMake Error at C:/Qt/Qt5.6.0/5.6/winrt_x64_msvc2015/lib/cmake/Qt5/Qt5Config.cmake:26 (find_package):
Could not find a package configuration file provided by "Qt5Designer" with
any of the following names:
Qt5DesignerConfig.cmake
qt5designer-config.cmake
Add the installation prefix of "Qt5Designer" to CMAKE_PREFIX_PATH or set
"Qt5Designer_DIR" to a directory containing one of the above files. If
"Qt5Designer" provides a separate development package or SDK, be sure it
has been installed.
Call Stack (most recent call first):
GUISupport/Qt/CMakeLists.txt:113 (find_package)